Matthias Schäfers, Adrian Lenkeit
The goal of our "Schüler experimentieren"-project is to build a functioning model of a radio interferometer. The advantage over a single antenna is that an interferometer has a substantially larger resolution. We conducted our first experiments with an acoustic interferometer in the school yard. The prototype consisted of a plank with a microphone attached to both ends. Encouraged by our first experiments, we decided to improve our acoustic interferometer further. However, due to deteriorating weather conditions, we had to continue our experiments indoors. Our measurements suffered from the reflection of the acoustic waves by walls and therefore we had to find an alternative.
In order to avoid the problems resulting from reflections and noise sources, we decided to build a microwave interferometer as microwaves are not reflected strongly by normal walls. However, due to their different oscillators, different satellite dishes cannot be simply combined and therefore we had to build an interferometer that can measure with a single detector. We tested several arrangements that exploit reflective surfaces to combine two signals from the same source on a single detector. The interferometers worked very well and we were able to show that theory and experiments agree well.
